An asteroid measuring about 30 metres in diameter buzzed close to Earth Wednesday, soaring past our planet at a distance that's closer than the moon.

The rock was only discovered last Friday, when astronomers “determined that it was actually aimed pretty close to the Earth,” said David Lane, observatory director at Saint Mary’s University in Halifax.

Asteroids pass our planet about 20 times a year and scientists said Wednesday’s asteroid posed no threat to Earth.

The asteroid 2014 DX110 came in about 350,000 kilometres from Earth at around 4 p.m. EST. In comparison, the average distance between Earth and the moon is approximately 385,000 kilometres.

Lane says it’s likely that asteroids aimed right at Earth will be the hardest ones to pinpoint.

“Chances are, it’s going to happen in the middle of the night and we won’t even know it’s going to happen,” he told CTV News.

Last year, the Chelyabinsk meteor took astronomers by surprise when it exploded over Russia, injuring more than 1,100 people, though only two seriously.

NASA’s Near-Earth Object Observations Program uses ground and space-based telescopes to detect and track asteroids in order to determine if any could be potentially dangerous to our planet.

According to NASA’s website, “enormous energies,” such as nuclear explosions would be required to deflect or fragment space rocks larger than a few hundred metres in diameter.

On the other hand, if scientists detect asteroids heading toward Earth several years in advance, a robotic spacecraft could be used to collide with the rock, nudging it off its trajectory.